New method for treating and prognosing cancer

ABSTRACT

The present invention relates to an in vitro method for determine the prognosis of the survival time of a patient suffering from a cancer comprising the steps consisting of i) determining the expression level of the couple DNMT3A/ISGF3γ in a sample from said patient, ii) comparing said expression level with a predetermined reference value and iii) providing a good prognosis when the expression level is lower than the predetermined reference value and a poor prognosis when the expression level is higher than the predetermined reference value. The invention also relates a compound which is a DNMT3A/ISGF3γ antagonist or a compound which is a DNMT3A/ISGF3γ gene expression inhibitor for use in the treatment and prevention of cancer.

FIELD OF THE INVENTION

The present invention relates to an in vitro method for determine theprognosis of the survival time of a patient suffering from a cancercomprising the steps consisting of i) determining the expression levelof the couple DNMT3A/ISGF3γ in a sample from said patient, ii) comparingsaid expression level with a predetermined reference value and iii)providing a good prognosis when the expression level is lower than thepredetermined reference value and a poor prognosis when the expressionlevel is higher than the predetermined reference value.

The invention also relates a compound which is a DNMT3A/ISGF3γantagonist or a compound which is a DNMT3A/ISGF3γ gene expressioninhibitor for use in the treatment and prevention of cancer.

BACKGROUND OF THE INVENTION

DNA methylation patterns are frequently aberrant in cancer cells. Thus,hypomethylation of intergenic regions can occur, leading totumorigenesis via the activation of transposable elements and increasedgenomic instability. Local hypomethylation of genes promoters canpromote oncogene expression, while local hypermethylation of the genespromoters can lead to loss of tumor suppressor function in cancer cells.Based on this last point, drug development has focused on DNAmethylation inhibitors with the goal of activating tumor suppressorgenes (TSG) silenced by DNA methylation. But in absence of specificity,a DNMT inhibitor can promote the demethylation of TSG but also ofoncogenes and transposable elements. Thus, the use of unspecific DNMTinhibitors can be anti-tumorigenic or pro-tumorigenic. Besides, thislast point is illustrated in several articles. Indeed, literaturereports that 5-aza-2′-deoxycytidine treatment (an unspecific DNMTinhibitor) increased the invasiveness of non-invasive breast cancer celllines MCF-7 cells and ZR-75-1 and dramatically induced pro-metastaticgenes [Chik F et al., 2011]. 5-aza-2′-deoxycytidine treatment is alsoreported as an inducer of glioma from astrocytes and as an enhancer oftumorigenic property of glioma cells. Nevertheless,5-aza-2′-deoxycytidine is approved by the Food and Drug Administrationof the United States for the myelodysplastic syndrome treatment, whereit demonstrates significant, although usually transient, improvement inpatient survival. Despite this undoubtable clinical utility, the dualeffect of the use of unspecific DNMT inhibitors provides evidence forthe development of specific DNMT inhibitors. In addition, specific DNMTinhibitors could also allow targeting of tumors harboring an aberrantfunctionality of a particular DNMT. The development of specific DNMTinhibitors could also reduced off-target effects associated with the useof unspecific DNMT inhibitors.

At present, several molecules are developed to specifically target aparticular DNMT. Thus, DNMT1 can be inhibited by using RG108, MG98 orProcainamide, DNMT3A while DNMT3B can be specifically inhibited by usingTheaflavin 3, 3′-digallate or NanaomycinA, respectively [Amato R et al.,2012; Kuck D et al., 2010; Kuck D et al., 2010; Lee B et al., 2005 andRajavelu A et al., 2001]. To identify these specific DNMT inhibitors,several strategies are developed: the docking-based virtual screeningmethods, the screening of natural products, the design and generation ofderivatives of DNMT inhibitors already known, the molecular modeling ofDNMT inhibitors by using crystal structure studies of DNMTs, or thedesign of siRNA targeting DNMTs [Kuck D et al., 2010; Medina-Franco J etal., 2011; Suzuki T et al., 2010; Yoo J et al., 2012; Yoo J et al., 2012and Venza M et al., 2013]. In a recent article, we demonstrated thatDNMT inhibitors can be also addressed against a specific DNMT/protein-xinteraction [Cheray M et al., 2013].

SUMMARY OF THE INVENTION

In the present study, the inventors asked the question to know whetherthe presence of interaction existing between DNMT3A and a DNMT3A-bindingprotein (D3A-BP) permit to identify a subpopulation of patientssuffering from glioblastoma multiformes (GBM) harboring a shorteroverall survival time and whose the glioma cells presented a resistancephenotype to the temozolomide/irradiation treatment. Then, they wantedto know whether it's possible to develop a strategy aiming tospecifically inhibit the DNMT3A/D3A-BP interaction associated with apoor prognosis of survival and/or response to thetemozolomide/irradiation treatment in order to increase the percentageof the temozolomide+irradiation-induced cell death, and the sensitivityof TMZ in a mice model of gliomagenesis.

Thus, the present invention relates to an in vitro method for determinethe prognosis of the survival time of a patient suffering from a cancercomprising the steps consisting of i) determining the expression levelof the couple DNMT3A/ISGF3γ in a sample from said patient, ii) comparingsaid expression level with a predetermined reference value and iii)providing a good prognosis when the expression level is lower than thepredetermined reference value and a poor prognosis when the expressionlevel is higher than the predetermined reference value.

The invention also relates a compound which is a DNMT3A/ISGF3γantagonist or a compound which is a DNMT3A/ISGF3γ gene expressioninhibitor for use in the treatment and prevention of cancer.

DETAILED DESCRIPTION OF THE INVENTION Prognostic and Predictive Methods

The first aspect of the invention relates to an in vitro method fordetermining the prognosis of the survival time of a patient sufferingfrom a cancer comprising the steps consisting of i) determining theexpression level of the couple DNMT3A/ISGF3γ in a sample from saidpatient, ii) comparing said expression level with a predeterminedreference value and iii) providing a good prognosis when the expressionlevel is lower than the predetermined reference value and a poorprognosis when the expression level is higher than the predeterminedreference value.

The invention also relates to an in vitro method for predicting thesurvival time of a patient suffering from a cancer and treated withconventional treatment comprising the steps consisting of i) determiningthe expression level of the couple DNMT3A/ISGF3γ in a sample from saidpatient, ii) comparing said expression level with a predeterminedreference value and iii) providing a good prognosis when the expressionlevel is lower than the predetermined reference value and a poorprognosis when the expression level is higher than the predeterminedreference value.

The invention also relates to an in vitro method for predicting theresponse of a patient suffering from a cancer and treated withconventional treatment comprising the steps consisting of i) determiningthe expression level of the couple DNMT3A/ISGF3γ in a sample from saidpatient, ii) comparing said expression level with a predeterminedreference value and iii) providing a good response when the expressionlevel is lower than the predetermined reference value and a poorresponse when the expression level is higher than the predeterminedreference value.

As used herein, the terms “conventional treatment” denote any compounds,combination of compounds, combination of chemotherapeutic treatment andradiotherapeutic agent and combination of chemotherapeutic treatment andradiation which may be used for the treatment of cancer. For example, inthe case of the treatment of glioblastoma, the conventional treatmentmay the use of a combination of the temozolomide and radiation.

Thus, the invention also relates to a method for predicting the survivaltime of a patient suffering from a glioblastoma and treated withradiation and temozolomide comprising the steps consisting of i)determining the expression level of the couple DNMT3A/ISGF3γ in a samplefrom said patient, ii) comparing said expression level with apredetermined reference value and iii) providing a good prognosis whenthe expression level is lower than the predetermined reference value anda poor prognosis when the expression level is higher than thepredetermined reference value.

The invention also relates to a method for predicting the response of apatient suffering from a glioblastoma and treated with radiation andtemozolomide comprising the steps consisting of i) determining theexpression level of the couple DNMT3A/ISGF3γ in a sample from saidpatient, ii) comparing said expression level with a predeterminedreference value and iii) providing a good response when the expressionlevel is lower than the predetermined reference value and a poorresponse when the expression level is higher than the predeterminedreference value.

In one embodiment, the cancer may be any solid or liquid cancer.Typically, the cancer may be selected from the group consisting of bileduct cancer (e.g. periphilar cancer, distal bile duct cancer,intrahepatic bile duct cancer), bladder cancer, bone cancer (e.g.osteoblastoma, osteochrondroma, hemangioma, chondromyxoid fibroma,osteosarcoma, chondrosarcoma, fibrosarcoma, malignant fibroushistiocytoma, giant cell tumor of the bone, chordoma, lymphoma, multiplemyeloma), brain and central nervous system cancer (e.g. meningioma,astocytoma, oligodendrogliomas, glioblastoma, ependymoma, gliomas,medulloblastoma, ganglioglioma, Schwannoma, germinoma,craniopharyngioma), breast cancer (e.g. ductal carcinoma in situ,infiltrating ductal carcinoma, infiltrating, lobular carcinoma, lobularcarcinoma in, situ, gynecomastia), Castleman disease (e.g. giant lymphnode hyperplasia, angiofollicular lymph node hyperplasia), cervicalcancer, colorectal cancer, endometrial cancer (e.g. endometrialadenocarcinoma, adenocanthoma, papillary serous adnocarcinroma, clearcell), esophagus cancer, gallbladder cancer (mucinous adenocarcinoma,small cell carcinoma), gastrointestinal carcinoid tumors (e.g.choriocarcinoma, chorioadenoma destruens), Hodgkin's disease,non-Hodgkin's lymphoma, Kaposi's sarcoma, kidney cancer (e.g. renal cellcancer), laryngeal and hypopharyngeal cancer, liver cancer (e.g.hemangioma, hepatic adenoma, focal nodular hyperplasia, hepatocellularcarcinoma), lung cancer (e.g. small cell lung cancer, non-small celllung cancer), mesothelioma, plasmacytoma, nasal cavity and paranasalsinus cancer (e.g. esthesioneuroblastoma, midline granuloma),nasopharyngeal cancer, neuroblastoma, oral cavity and oropharyngealcancer, ovarian cancer, pancreatic cancer, penile cancer, pituitarycancer, prostate cancer, retinoblastoma, rhabdomyosarcoma (e.g.embryonal rhabdomyosarcoma, alveolar rhabdomyosarcoma, pleomorphicrhabdomyosarcoma), salivary gland cancer, skin cancer (e.g. melanoma,nonmelanoma skin cancer), stomach cancer, testicular cancer (e.g.seminoma, nonseminoma germ cell cancer), thymus cancer, thyroid cancer(e.g. follicular carcinoma, anaplastic carcinoma, poorly differentiatedcarcinoma, medullary thyroid carcinoma, thyroid lymphoma), vaginalcancer, vulvar cancer, and uterine cancer (e.g. uterine leiomyosarcoma).

In a particular embodiment, the glioblastoma is a glioblastomamultiforme.

Typically, the sample according to the invention may be a blood, plasma,serum sample or a cancer biopsy. In a particular embodiment, said sampleis a glioblastoma biopsy.

As used herein, the term “DNMT3A” for “DNA methyltransferase 3A” (EntrezGene ID number: 1788; mRNA sequence reference: NM_022552.4; proteinsequence reference: Q9Y6K1) designed a de novo DNA methyltransferasei.e. an enzyme responsible for the establishment of de novo genomic DNAmethylation patterns and, as such, involved in normal development aswell as in many diseases including cancer.

Protein sequence of DNMT3A (SEQ ID NO:3) is:

MPAMPSSGPGDTSSSAAEREEDRKDGEEQEEPRGKEERQEPSTTARKVGRPGRKRKHPPVESGDTPKDPAVISKSPSMAQDSGASELLPNGDLEKRSEPQPEEGSPAGGQKGGAPAEGEGAAETLPEASRAVENGCCTPKEGRGAPAEAGKEQKETNIESMKMEGSRGRLRGGLGWESSLRQRPMPRLTFQAGDPYYISKRKRDEWLARWKREAEKKAKVIAGMNAVEENQGPGESQKVEEASPPAVQQPTDPASPTVATTPEPVGSDAGDKNATKAGDDEPEYEDGRGFGIGELVWGKLRGFSWWPGRIVSWWMTGRSRAAEGTRWVMWFGDGKFSVVCVEKLMPLSSFCSAFHQATYNKQPMYRKAIYEVLQVASSRAGKLFPVCHDSDESDTAKAVEVQNKPMIEWALGGFQPSGPKGLEPPEEEKNPYKEVYTDMWVEPEAAAYAPPPPAKKPRKSTAEKPKVKEIIDERTRERLVYEVRQKCRNIEDICISCGSLNVTLEHPLFVGGMCQNCKNCFLECAYQYDDDGYQSYCTICCGGREVLMCGNNNCCRCFCVECVDLLVGPGAAQAAIKEDPWNCYMCGHKGTYGLLRRREDWPSRLQMFFANNHDQEFDPPKVYPPVPAEKRKPIRVLSLFDGIATGLLVLKDLGIQVDRYIASEVCEDSITVGMVRHQGKIMYVGDVRSVTQKHIQEWGPFDLVIGGSPCNDLSIVNPARKGLYEGTGRLFFEFYRLLHDARPKEGDDRPFFWLFENVVAMGVSDKRDISRFLESNPVMIDAKEVSAAHRARYFWGNLPGMNRPLASTVNDKLELQECLEHGRIAKFSKVRTITTRSNSIKQGKDQHFPVFMNEKEDILWCTEMERVFGFPVHYTDVSNMSRLARQRLLGRSWSVPVIRH LFAPLKEYFACV

As used herein, the term “ISGF3γ” (Entrez Gene ID number: 10379; mRNAsequence reference: NM_006084.4; protein sequence reference: Q00978)denotes a Transcription factor that mediates signaling by type I IFNs.ISGF3γ binds to the IFN stimulated response element (ISRE) to activatethe transcription of interferon stimulated genes, which drive the cellin an antiviral state.

In another embodiment, the invention relates to an in vitro method fordetermine the prognosis of the overall survival (OS) of a patientsuffering from a cancer comprising the steps consisting of i)determining the expression level of the couple DNMT3A/ISGF3γ in a samplefrom said patient, ii) comparing said expression level with apredetermined reference value and iii) providing a good prognosis whenthe expression level is lower than the predetermined reference value anda poor prognosis when the expression level is higher than thepredetermined reference value.

In another embodiment, the invention also relates to a method forpredicting the overall survival (OS) of a patient suffering from acancer and treated with conventional treatment comprising the stepsconsisting of i) determining the expression level of the coupleDNMT3A/ISGF3γ in a sample from said patient, ii) comparing saidexpression level with a predetermined reference value and iii) providinga good prognosis when the expression level is lower than thepredetermined reference value and a poor prognosis when the expressionlevel is higher than the predetermined reference value.

In another embodiment, the invention also relates to a method forpredicting the overall survival (OS) of a patient suffering from aglioblastoma and treated with radiation and temozolomide comprising thesteps consisting of i) determining the expression level of the coupleDNMT3A/ISGF3γ in a sample from said patient, ii) comparing saidexpression level with a predetermined reference value and iii) providinga good prognosis when the expression level is lower than thepredetermined reference value and a poor prognosis when the expressionlevel is higher than the predetermined reference value.

As used herein, the term “Overall survival (OS)” denotes the percentageof people in a study or treatment group who are still alive for acertain period of time after they were diagnosed with or startedtreatment for a disease, such as a cancer (according to the invention).

As used herein, the term “Good Prognosis” denotes a patient with morethan 50% chance of survival for the next 3 years after the treatment.

The invention also relates to a method for predicting the responsivenessof a patient affected with a glioblastoma to a temozolomide andradiation treatment comprising the steps consisting of i) determiningthe expression level of the couple DNMT3A/ISGF3γ in a sample from saidpatient ii) comparing the expression level determined at step i) withits predetermined reference value wherein when the expression leveldetermined at step i) is lower than its predetermined reference valuesthen the responsiveness of the patient to the treatment is good, andwhen the expression level determined at step i) is higher than itspredetermined reference value then the responsiveness of the patient tothe treatment is bad.

In one embodiment and according to the methods of the invention, thedetermination of the expression level of the couple DNMT3A/ISGF3γ may bedetermined before or after the beginning of the treatment of thepatient.

In another embodiment, the patient affected with a glioblastoma ismainly treated with a standard treatment consisting of maximal surgicalresection, radiotherapy, and concomitant adjuvant chemotherapy withtemozolomide.

The term “determining the expression level of” as used above includesqualitative and/or quantitative detection (measuring levels) with orwithout reference to a control. Typically expression level of the coupleDNMT3A/ISGF3γ may be measured for example by enzyme-labeled and mediatedimmunoassays (such as ELISA), flow cytometry assessment or qRT-PCRperformed on the sample.

The “reference value” may be a healthy subject, i.e. a subject who doesnot suffer from any cancer and particularly glioblastoma. Particularly,said control is a healthy subject.

Detection of the expression level of the couple DNMT3A/ISGF3γ in thesample may be performed by measuring the level of DNMT3A/ISGF3γ proteinsor the DNMT3A/ISGF3γ genes.

In the case of the detection of DNMT3A/ISGF3γ proteins, the methods maycomprise contacting a sample with a binding partner capable ofselectively interacting with DNMT3A/ISGF3γ proteins present in thesample. The binding partner is generally an antibody that may bepolyclonal or monoclonal, particularly monoclonal.

The presence of the protein can be detected using standardelectrophoretic and immunodiagnostic techniques, including immunoassayssuch as competition, direct reaction, or sandwich type assays. Suchassays include, but are not limited to, Western blots; agglutinationtests; enzyme-labeled and mediated immunoassays, such as ELISAs;biotin/avidin type assays; radioimmunoassays; immunoelectrophoresis;immunoprecipitation, etc. The reactions generally include revealinglabels such as fluorescent, chemiluminescent, radioactive, enzymaticlabels or dye molecules, or other methods for detecting the formation ofa complex between the antigen and the antibody or antibodies reactedtherewith.

The aforementioned assays generally involve separation of unboundprotein in a liquid phase from a solid phase support to whichantigen-antibody complexes are bound. Solid supports which can be usedin the practice of the invention include substrates such asnitrocellulose (e. g., in membrane or microtiter well form);polyvinylchloride (e. g., sheets or microtiter wells); polystyrene latex(e.g., beads or microtiter plates); polyvinylidine fluoride; diazotizedpaper; nylon membranes; activated beads, magnetically responsive beads,and the like.

More particularly, an ELISA method can be used, wherein the wells of amicrotiter plate are coated with a set of antibodies against theproteins to be tested. A sample containing or suspected of containingthe marker protein is then added to the coated wells. After a period ofincubation sufficient to allow the formation of antibody-antigencomplexes, the plate(s) can be washed to remove unbound moieties and adetectably labeled secondary binding molecule is added. The secondarybinding molecule is allowed to react with any captured sample markerprotein, the plate is washed and the presence of the secondary bindingmolecule is detected using methods well known in the art.

Various immunoenzymatic staining methods are known in the art fordetecting a protein of interest. For example, immunoenzymaticinteractions can be visualized using different enzymes such asperoxidase, alkaline phosphatase, or different chromogens such as DAB,AEC, or Fast Red; or fluorescent labels such as FITC, Cy3, Cy5, Cy7,Alexafluors, etc. Counterstains may include H&E, DAPI, Hoechst, so longas such stains are compatable with other detection reagents and thevisualization strategy used. As known in the art, amplification reagentsmay be used to intensify staining signal. For example, tyramide reagentsmay be used. The staining methods of the present invention may beaccomplished using any suitable method or system as would be apparent toone of skill in the art, including automated, semi-automated or manualsystems.

The method of the invention may comprise a further step consisting ofcomparing DNMT3A/ISGF3γ proteins expression with a control reference.

In the case of detection of the DNMT3A/ISGF3γ genes, the term“expression level of DNMT3A/ISGF3γ” refers to an amount or aconcentration of a transcription product, for instance mRNA coding forDNMT3A/ISGF3γ genes. Typically, a level of mRNA expression can beexpressed in units such as transcripts per cell or nanograms permicrogram of tissue. A level of protein can be expressed as nanogramsper microgram of tissue or nanograms per milliliter of a culture medium,for example. Alternatively, relative units can be employed to describean expression level.

Measuring the expression level of a gene can be performed by a varietyof techniques well known in the art.

Typically, the expression level of a gene may be determined bydetermining the quantity of mRNA. Methods for determining the quantityof mRNA are well known in the art. For example the nucleic acidcontained in the samples (e.g., cell or tissue prepared from thepatient) is first extracted according to standard methods, for exampleusing lytic enzymes or chemical solutions or extracted bynucleic-acid-binding resins following the manufacturer's instructions.The extracted mRNA is then detected by hybridization (e. g., Northernblot analysis, in situ hybridization) and/or amplification (e.g.,RT-PCR).

Other methods of Amplification include ligase chain reaction (LCR),transcription-mediated amplification (TMA), strand displacementamplification (SDA) and nucleic acid sequence based amplification(NASBA).

Nucleic acids having at least 10 nucleotides and exhibiting sequencecomplementarity or homology to the mRNA of interest herein find utilityas hybridization probes or amplification primers. It is understood thatsuch nucleic acids need not be identical, but are typically at leastabout 80% identical to the homologous region of comparable size, moreparticularly 85% identical and even more particularly 90-95% identical.In certain embodiments, it will be advantageous to use nucleic acids incombination with appropriate means, such as a detectable label, fordetecting hybridization.

Typically, the nucleic acid probes include one or more labels, forexample to permit detection of a target nucleic acid molecule using thedisclosed probes. In various applications, such as in situ hybridizationprocedures, a nucleic acid probe includes a label (e.g., a detectablelabel). A “detectable label” is a molecule or material that can be usedto produce a detectable signal that indicates the presence orconcentration of the probe (particularly the bound or hybridized probe)in a sample. Thus, a labeled nucleic acid molecule provides an indicatorof the presence or concentration of a target nucleic acid sequence(e.g., genomic target nucleic acid sequence) (to which the labeleduniquely specific nucleic acid molecule is bound or hybridized) in asample. A label associated with one or more nucleic acid molecules (suchas a probe generated by the disclosed methods) can be detected eitherdirectly or indirectly. A label can be detected by any known or yet tobe discovered mechanism including absorption, emission and/or scatteringof a photon (including radio frequency, microwave frequency, infraredfrequency, visible frequency and ultra-violet frequency photons).Detectable labels include colored, fluorescent, phosphorescent andluminescent molecules and materials, catalysts (such as enzymes) thatconvert one substance into another substance to provide a detectabledifference (such as by converting a colorless substance into a coloredsubstance or vice versa, or by producing a precipitate or increasingsample turbidity), haptens that can be detected by antibody bindinginteractions, and paramagnetic and magnetic molecules or materials.

Particular examples of detectable labels include fluorescent molecules(or fluorochromes). Numerous fluorochromes are known to those of skillin the art, and can be selected, for example from Life Technologies(formerly Invitrogen), e.g., see, The Handbook—A Guide to FluorescentProbes and Labeling Technologies). Examples of particular fluorophoresthat can be attached (for example, chemically conjugated) to a nucleicacid molecule (such as a uniquely specific binding region) are providedin U.S. Pat. No. 5,866,366 to Nazarenko et al., such as4-acetamido-4′-isothiocyanatostilbene-2,2′ disulfonic acid, acridine andderivatives such as acridine and acridine isothiocyanate,5-(2′-aminoethyl) aminonaphthalene-1-sulfonic acid (EDANS), 4-amino-N-[3vinylsulfonyl)phenyl]naphthalimide-3,5 disulfonate (Lucifer Yellow VS),N-(4-anilino-1-naphthyl)maleimide, antllranilamide, Brilliant Yellow,coumarin and derivatives such as coumarin, 7-amino-4-methylcoumarin(AMC, Coumarin 120), 7-amino-4-trifluoromethylcouluarin (Coumarin 151);cyanosine; 4′,6-diarninidino-2-phenylindole (DAPI);5′,5″dibromopyrogallol-sulfonephthalein (Bromopyrogallol Red);7-diethylamino-3-(4′-isothiocyanatophenyl)-4-methylcoumarin;diethylenetriamine pentaacetate;4,4′-diisothiocyanatodihydro-stilbene-2,2′-disulfonic acid;4,4′-diisothiocyanatostilbene-2,2′-disulforlic acid; 5-[dimethylamino]naphthalene-1-sulfonyl chloride (DNS, dansyl chloride);4-(4′-dimethylaminophenylazo)benzoic acid (DABCYL);4-dimethylaminophenylazophenyl-4′-isothiocyanate (DABITC); eosin andderivatives such as eosin and eosin isothiocyanate; erythrosin andderivatives such as erythrosin B and erythrosin isothiocyanate;ethidium; fluorescein and derivatives such as 5-carboxyfluorescein(FAM), 5-(4,6diclllorotriazin-2-yDarninofluorescein (DTAF),2′7′dimethoxy-4′5′-dichloro-6-carboxyfluorescein (JOE), fluorescein,fluorescein isothiocyanate (FITC), and QFITC Q(RITC);2′,7′-difluorofluorescein (OREGON GREEN®); fluorescamine; IR144; IR1446;Malachite Green isothiocyanate; 4-methylumbelliferone; orthocresolphthalein; nitrotyrosine; pararosaniline; Phenol Red;B-phycoerythrin; o-phthaldialdehyde; pyrene and derivatives such aspyrene, pyrene butyrate and succinimidyl 1-pyrene butyrate; Reactive Red4 (Cibacron Brilliant Red 3B-A); rhodamine and derivatives such as6-carboxy-X-rhodamine (ROX), 6-carboxyrhodamine (R6G), lissaminerhodamine B sulfonyl chloride, rhodamine (Rhod), rhodamine B, rhodamine123, rhodamine X isothiocyanate, rhodamine green, sulforhodamine B,sulforhodamine 101 and sulfonyl chloride derivative of sulforhodamine101 (Texas Red); N,N,N′,N′-tetramethyl-6-carboxyrhodamine (TAMRA);tetramethyl rhodamine; tetramethyl rhodamine isothiocyanate (TRITC);riboflavin; rosolic acid and terbium chelate derivatives. Other suitablefluorophores include thiol-reactive europium chelates which emit atapproximately 617 mn (Heyduk and Heyduk, Analyt. Biochem. 248:216-27,1997; J. Biol. Chem. 274:3315-22, 1999), as well as GFP, Lissamine™,diethylaminocoumarin, fluorescein chlorotriazinyl, naphthofluorescein,4,7-dichlororhodamine and xanthene (as described in U.S. Pat. No.5,800,996 to Lee et al.) and derivatives thereof. Other fluorophoresknown to those skilled in the art can also be used, for example thoseavailable from Life Technologies (Invitrogen; Molecular Probes (Eugene,Oreg.)) and including the ALEXA FLUOR® series of dyes (for example, asdescribed in U.S. Pat. Nos. 5,696,157, 6,130,101 and 6,716,979), theBODIPY series of dyes (dipyrrometheneboron difluoride dyes, for exampleas described in U.S. Pat. Nos. 4,774,339, 5,187,288, 5,248,782,5,274,113, 5,338,854, 5,451,663 and 5,433,896), Cascade Blue (an aminereactive derivative of the sulfonated pyrene described in U.S. Pat. No.5,132,432) and Marina Blue (U.S. Pat. No. 5,830,912).

In addition to the fluorochromes described above, a fluorescent labelcan be a fluorescent nanoparticle, such as a semiconductor nanocrystal,e.g., a QUANTUM DOT™ (obtained, for example, from Life Technologies(QuantumDot Corp, Invitrogen Nanocrystal Technologies, Eugene, Oreg.);see also, U.S. Pat. Nos. 6,815,064; 6,682,596; and 6,649, 138).Semiconductor nanocrystals are microscopic particles havingsize-dependent optical and/or electrical properties. When semiconductornanocrystals are illuminated with a primary energy source, a secondaryemission of energy occurs of a frequency that corresponds to the handgapof the semiconductor material used in the semiconductor nanocrystal.This emission can be detected as colored light of a specific wavelengthor fluorescence. Semiconductor nanocrystals with different spectralcharacteristics are described in e.g., U.S. Pat. No. 6,602,671.Semiconductor nanocrystals that can be coupled to a variety ofbiological molecules (including dNTPs and/or nucleic acids) orsubstrates by techniques described in, for example, Bruchez et al.,Science 281:20132016, 1998; Chan et al., Science 281:2016-2018, 1998;and U.S. Pat. No. 6,274,323. Formation of semiconductor nanocrystals ofvarious compositions are disclosed in, e.g., U.S. Pat. Nos. 6,927,069;6,914,256; 6,855,202; 6,709,929; 6,689,338; 6,500,622; 6,306,736;6,225,198; 6,207,392; 6,114,038; 6,048,616; 5,990,479; 5,690,807;5,571,018; 5,505,928; 5,262,357 and in U.S. Patent Publication No.2003/0165951 as well as PCT Publication No. 99/26299 (published May 27,1999). Separate populations of semiconductor nanocrystals can beproduced that are identifiable based on their different spectralcharacteristics. For example, semiconductor nanocrystals can be producedthat emit light of different colors based on their composition, size orsize and composition. For example, quantum dots that emit light atdifferent wavelengths based on size (565 mn, 655 mn, 705 mn, or 800 mnemission wavelengths), which are suitable as fluorescent labels in theprobes disclosed herein are available from Life Technologies (Carlshad,Calif.).

Additional labels include, for example, radioisotopes (such as 3H),metal chelates such as DOTA and DPTA chelates of radioactive orparamagnetic metal ions like Gd3+, and liposomes.

Detectable labels that can be used with nucleic acid molecules alsoinclude enzymes, for example horseradish peroxidase, alkalinephosphatase, acid phosphatase, glucose oxidase, beta-galactosidase,beta-glucuronidase, or beta-lactamase.

Alternatively, an enzyme can be used in a metallographic detectionscheme. For example, silver in situ hyhridization (SISH) proceduresinvolve metallographic detection schemes for identification andlocalization of a hybridized genomic target nucleic acid sequence.Metallographic detection methods include using an enzyme, such asalkaline phosphatase, in combination with a water-soluble metal ion anda redox-inactive substrate of the enzyme. The substrate is converted toa redox-active agent by the enzyme, and the redoxactive agent reducesthe metal ion, causing it to form a detectable precipitate. (See, forexample, U.S. Patent Application Publication No. 2005/0100976, PCTPublication No. 2005/003777 and U.S. Patent Application Publication No.2004/0265922). Metallographic detection methods also include using anoxido-reductase enzyme (such as horseradish peroxidase) along with awater soluble metal ion, an oxidizing agent and a reducing agent, againto form a detectable precipitate. (See, for example, U.S. Pat. No.6,670,113).

Probes made using the disclosed methods can be used for nucleic aciddetection, such as ISH procedures (for example, fluorescence in situhybridization (FISH), chromogenic in situ hybridization (CISH) andsilver in situ hybridization (SISH)) or comparative genomichybridization (CGH).

In situ hybridization (ISH) involves contacting a sample containingtarget nucleic acid sequence (e.g., genomic target nucleic acidsequence) in the context of a metaphase or interphase chromosomepreparation (such as a cell or tissue sample mounted on a slide) with alabeled probe specifically hybridizable or specific for the targetnucleic acid sequence (e.g., genomic target nucleic acid sequence). Theslides are optionally pretreated, e.g., to remove paraffin or othermaterials that can interfere with uniform hybridization. The sample andthe probe are both treated, for example by heating to denature thedouble stranded nucleic acids. The probe (formulated in a suitablehybridization buffer) and the sample are combined, under conditions andfor sufficient time to permit hybridization to occur (typically to reachequilibrium). The chromosome preparation is washed to remove excessprobe, and detection of specific labeling of the chromosome target isperformed using standard techniques.

For example, a biotinylated probe can be detected usingfluorescein-labeled avidin or avidin-alkaline phosphatase. Forfluorochrome detection, the fluorochrome can be detected directly, orthe samples can be incubated, for example, with fluoresceinisothiocyanate (FITC)-conjugated avidin. Amplification of the FITCsignal can be effected, if necessary, by incubation withbiotin-conjugated goat antiavidin antibodies, washing and a secondincubation with FITC-conjugated avidin. For detection by enzymeactivity, samples can be incubated, for example, with streptavidin,washed, incubated with biotin-conjugated alkaline phosphatase, washedagain and pre-equilibrated (e.g., in alkaline phosphatase (AP) buffer).For a general description of in situ hybridization procedures, see,e.g., U.S. Pat. No. 4,888,278.

Numerous procedures for FISH, CISH, and SISH are known in the art. Forexample, procedures for performing FISH are described in U.S. Pat. Nos.5,447,841; 5,472,842; and 5,427,932; and for example, in Pirlkel et al.,Proc. Natl. Acad. Sci. 83:2934-2938, 1986; Pinkel et al., Proc. Natl.Acad. Sci. 85:9138-9142, 1988; and Lichter et al., Proc. Natl. Acad.Sci. 85:9664-9668, 1988. CISH is described in, e.g., Tanner et al.,Am. 1. Pathol. 157:1467-1472, 2000 and U.S. Pat. No. 6,942,970.Additional detection methods are provided in U.S. Pat. No. 6,280,929.

Numerous reagents and detection schemes can be employed in conjunctionwith FISH, CISH, and SISH procedures to improve sensitivity, resolution,or other desirable properties. As discussed above probes labeled withfluorophores (including fluorescent dyes and QUANTUM DOTS®) can bedirectly optically detected when performing FISH. Alternatively, theprobe can be labeled with a nonfluorescent molecule, such as a hapten(such as the following non-limiting examples: biotin, digoxigenin, DNP,and various oxazoles, pyrrazoles, thiazoles, nitroaryls, benzofurazans,triterpenes, ureas, thioureas, rotenones, coumarin, courmarin-basedcompounds, Podophyllotoxin, Podophyllotoxin-based compounds, andcombinations thereof), ligand or other indirectly detectable moiety.Probes labeled with such non-fluorescent molecules (and the targetnucleic acid sequences to which they bind) can then be detected bycontacting the sample (e.g., the cell or tissue sample to which theprobe is bound) with a labeled detection reagent, such as an antibody(or receptor, or other specific binding partner) specific for the chosenhapten or ligand. The detection reagent can be labeled with afluorophore (e.g., QUANTUM DOT®) or with another indirectly detectablemoiety, or can be contacted with one or more additional specific bindingagents (e.g., secondary or specific antibodies), which can be labeledwith a fluorophore.

In other examples, the probe, or specific binding agent (such as anantibody, e.g., a primary antibody, receptor or other binding agent) islabeled with an enzyme that is capable of converting a fluorogenic orchromogenic composition into a detectable fluorescent, colored orotherwise detectable signal (e.g., as in deposition of detectable metalparticles in SISH). As indicated above, the enzyme can be attacheddirectly or indirectly via a linker to the relevant probe or detectionreagent. Examples of suitable reagents (e.g., binding reagents) andchemistries (e.g., linker and attachment chemistries) are described inU.S. Patent Application Publication Nos. 2006/0246524; 2006/0246523, and2007/01 17153.

It will be appreciated by those of skill in the art that byappropriately selecting labelled probe-specific binding agent pairs,multiplex detection schemes can be produced to facilitate detection ofmultiple target nucleic acid sequences (e.g., genomic target nucleicacid sequences) in a single assay (e.g., on a single cell or tissuesample or on more than one cell or tissue sample). For example, a firstprobe that corresponds to a first target sequence can be labelled with afirst hapten, such as biotin, while a second probe that corresponds to asecond target sequence can be labelled with a second hapten, such asDNP. Following exposure of the sample to the probes, the bound probescan be detected by contacting the sample with a first specific bindingagent (in this case avidin labelled with a first fluorophore, forexample, a first spectrally distinct QUANTUM DOT®, e.g., that emits at585 mn) and a second specific binding agent (in this case an anti-DNPantibody, or antibody fragment, labelled with a second fluorophore (forexample, a second spectrally distinct QUANTUM DOT®, e.g., that emits at705 mn). Additional probes/binding agent pairs can be added to themultiplex detection scheme using other spectrally distinct fluorophores.Numerous variations of direct, and indirect (one step, two step or more)can be envisioned, all of which are suitable in the context of thedisclosed probes and assays.

Probes typically comprise single-stranded nucleic acids of between 10 to1000 nucleotides in length, for instance of between 10 and 800, moreparticularly of between 15 and 700, typically of between 20 and 500.Primers typically are shorter single-stranded nucleic acids, of between10 to 25 nucleotides in length, designed to perfectly or almostperfectly match a nucleic acid of interest, to be amplified. The probesand primers are “specific” to the nucleic acids they hybridize to, i.e.they particularly hybridize under high stringency hybridizationconditions (corresponding to the highest melting temperature Tm, e.g.,50% formamide, 5× or 6×SCC. SCC is a 0.15 M NaCl, 0.015 M Na-citrate).

The nucleic acid primers or probes used in the above amplification anddetection method may be assembled as a kit. Such a kit includesconsensus primers and molecular probes. A particular kit also includesthe components necessary to determine if amplification has occurred. Thekit may also include, for example, PCR buffers and enzymes; positivecontrol sequences, reaction control primers; and instructions foramplifying and detecting the specific sequences.

In a particular embodiment, the methods of the invention comprise thesteps of providing total RNAs extracted from cumulus cells andsubjecting the RNAs to amplification and hybridization to specificprobes, more particularly by means of a quantitative orsemi-quantitative RT-PCR.

In another particular embodiment, the expression level is determined byDNA chip analysis. Such DNA chip or nucleic acid microarray consists ofdifferent nucleic acid probes that are chemically attached to asubstrate, which can be a microchip, a glass slide or amicrosphere-sized bead. A microchip may be constituted of polymers,plastics, resins, polysaccharides, silica or silica-based materials,carbon, metals, inorganic glasses, or nitrocellulose. Probes comprisenucleic acids such as cDNAs or oligonucleotides that may be about 10 toabout 60 base pairs. To determine the expression level, a sample from atest subject, optionally first subjected to a reverse transcription, islabelled and contacted with the microarray in hybridization conditions,leading to the formation of complexes between target nucleic acids thatare complementary to probe sequences attached to the microarray surface.The labelled hybridized complexes are then detected and can bequantified or semi-quantified. Labelling may be achieved by variousmethods, e.g. by using radioactive or fluorescent labelling. Manyvariants of the microarray hybridization technology are available to theman skilled in the art (see e.g. the review by Hoheisel, Nature Reviews,Genetics, 2006, 7:200-210).

Expression level of a gene may be expressed as absolute expression levelor normalized expression level. Typically, expression levels arenormalized by correcting the absolute expression level of a gene bycomparing its expression to the expression of a gene that is not arelevant for determining the cancer stage of the patient, e.g., ahousekeeping gene that is constitutively expressed. Suitable genes fornormalization include housekeeping genes such as the actin gene ACTB,ribosomal 18S gene, GUSB, PGK1 and TFRC. According to the invention thehousekeeping genes used were GAPDH, GUSB, TBP and ABL1. Thisnormalization allows the comparison of the expression level in onesample, e.g., a patient sample, to another sample, or between samplesfrom different sources.

Typically, a “threshold value”, “threshold level”, “reference value” or“cut-off value” can be determined experimentally, empirically, ortheoretically. A threshold value can also be arbitrarily selected basedupon the existing experimental and/or clinical conditions, as would berecognized by a person of ordinary skilled in the art. Particularly, theperson skilled in the art may compare the expression levels of thecouple DNMT3A/ISGF3γ obtained according to the method of the inventionwith a defined threshold value.

Particularly, said threshold value is the mean expression level of thecouple DNMT3A/ISGF3γ of a population of healthy individuals. As usedherein, the term “healthy individual” denotes a human which is known tobe healthy, i.e. which does not suffer from a cancer and in particularfrom a glioblastoma and does not need any medical care.

Typically, the skilled person in the art may determine the expressionlevel of the couple DNMT3A/ISGF3γ in a biological sample, particularly abiopsy of a glioblastoma cancer for example, of 100 individuals known tobe healthy. The mean value of the obtained expression levels is thendetermined, according to well known statistical analysis, so as toobtain the mean expression level of the couple DNMT3A/ISGF3γ. Said valueis then considered as being normal and thus constitutes a thresholdvalue. By comparing the expression levels of the couple DNMT3A/ISGF3γ tothis threshold value, the physician is then able to classify andprognostic the cancer.

Accordingly, the physician would be able to adapt and optimizeappropriate medical care of a subject in a critical and life-threateningcondition suffering from cancer. The determination of said prognosis ishighly appropriate for follow-up care and clinical decision making.

The present invention also relates to kits useful for the methods of theinvention, comprising means for detecting DNMT3A/ISGF3γ expression.

According to the invention, the kits of the invention may comprise ananti-DNMT3A protein antibody and an anti-ISGF3γ; and another moleculecoupled with a signalling system which binds to said DNMT3A/ISGF3γantibodies or any molecule which bind to the mRNA of DNMT3A/ISGF3γ geneslike a probe.

Typically, the antibodies or combination of antibodies are in the formof solutions ready for use. In one embodiment, the kit comprisescontainers with the solutions ready for use. Any other forms areencompassed by the present invention and the man skilled in the art canroutinely adapt the form to the use in immunohistochemistry.

In another embodiment, the invention relates to an in vitro method formonitoring a patient's response cancer treatment which comprises a stepof measuring the expression level of the couple DNMT3A/ISGF3γ, in asample from a patient.

Thus, the present invention relates to the use of the coupleDNMT3A/ISGF3γ as a biomarker for the monitoring of anti-cancer therapiesand more particularly an anti-glioblastoma therapy.

Another aspect of the invention relates to a compound which is anantagonist of the couple DNMT3A/ISGF3γ or an inhibitor of the expressionof the couple DNMT3A/ISGF3γ for use in the treatment of patientsuffering of a cancer with a high expression level of the coupleDNMT3A/ISGF3γ.

Particularly, the invention also relates to a compound which is anantagonist of the couple DNMT3A/ISGF3γ or an inhibitor of the expressionof the couple DNMT3A/ISGF3γ for use in the treatment of patientsuffering from a glioblastoma with a high expression level of the coupleDNMT3A/ISGF3γ.

Therapeutic Method

A second aspect of the invention relates to a compound which is aDNMT3A/ISGF3γ antagonist or a compound which is a DNMT3A/ISGF3γ geneexpression inhibitor for use in the treatment and prevention of cancer.

By “DNMT3A/ISGF3γ antagonist” is meant a natural or synthetic compoundthat has a biological effect opposite to that of a natural ligand ofDNMT3A and/or ISGF3γ. According to the invention, the antagonist bindsto the couple DNMT3A/ISGF3γ and blocks the action of these proteins bycompeting with the ligand of these proteins. An antagonist is defined byits ability to block the actions of a natural ligand. The term“DNMT3A/ISGF3γ antagonist” refers to any DNMT3A/ISGF3γ antagonist thatis currently known in the art or that will be identified in the future,and includes any chemical entity that, upon administration to a subject,results in inhibition of a biological activity associated withactivation of the DNMT3A/ISGF3γ proteins in the subject, including anyof the downstream biological effects otherwise resulting from thebinding to DNMT3A/ISGF3γ of its natural ligands. Alternatively, such anantagonist can act by occupying the ligand binding site or a portionthereof of DNMT3A/ISGF3γ proteins, thereby making the receptorinaccessible to its natural ligand so that its normal biologicalactivity is prevented or reduced. In one embodiment, the antagonist ofthe invention can block the binding of the protein DNMT3A to the proteinISGF3γ. Thus, a “DNMT3A/ISGF3γ antagonist” can be a compound which bindsto the DNMT3A protein or to the ISGF3γ protein.

According to the invention, a DNMT3A/ISGF3γ antagonist may bind to theDNMT3A protein at the position 85-99, 103-129, 178-207, 235-246,256-273, 331-360, 409-433 or 547-574 of SEQ ID NO: 3 and inhibits theDNMT3A/ISGF3γ interaction.

Thus, the present invention also relates to a method of screening acandidate compound for use as a drug for the prevention and treatment ofcancer in a subject in need thereof, wherein the method comprises thesteps of: i) providing candidate compounds and ii) selecting candidatecompounds that block or antagonise DNMT3A/ISGF3γ.

In a further aspect, the present invention relates to a method ofscreening a candidate compound for use as a drug for the treatment andprevention of cancer in a subject in need thereof, wherein the methodcomprises the steps of:

(i) providing the couple DNMT3A/ISGF3γ, providing a cell, tissue sampleor organism expressing DNMT3A/ISGF3γ,

(ii) providing a candidate compound such as small organic molecule,intra-antibodies, peptide or polypeptide,

(iii) measuring the activity of DNMT3A/ISGF3γ,

(iv) and selecting positively candidate compounds that blocksDNMT3A/ISGF3γ, blocks the action of DNMT3A/ISGF3γ or inhibitsDNMT3A/ISGF3γ expression.

To identify a compound able to block the interaction between DNMT3A andISGF3γ or inhibits DNMT3A/ISGF3γ expression, a test may be used. Forexample, a test using bioluminescence resonance energy transfer (BRET)system for assaying DNMT3A/ISGF3 interactions and identifying moleculehaving the ability to inhibit this interaction can be develop. For thispurpose, cDNA of interDNMT3A and ISGF3g will be inserted in vectorsdesigned for Bioluminescence Resonance Energy Transfer (BRET)experiments (pEYFP and phRluc, Invitrogen). Next, these vectors will betransfected in U251 cells (a GBM cell lines). Once the assay will bevalidated, BRET will be used for the screening of compounds libraries: adecrease of signal will interpreted as the highlighting of a moleculehaving the ability to inhibit the DNMT3A/ISGF3g interaction.

By “DNMT3A/ISGF3γ gene expression inhibitor” is meant a natural orsynthetic compound which inhibits the expression of the DNMT3A geneexpression or the ISGF3γ gene expression or both.

To identify such compound a test may be used. For example, to analyzethe ability of a compound to inhibit the DNMT3A and ISGF3 expression,qPCR and ELISA experiments can be performed.

The invention also relates to i) compound according to the invention,and ii) a chemotherapeutic agent, as a combined preparation forsimultaneous, separate or sequential for use in the treatment andprevention of cancer.

The invention also relates to i) compound according to the invention,and ii) a chemotherapeutic agent and iii) a radiotherapy or aradiotherapeutic agent, as a combined preparation for simultaneous,separate or sequential for use in the treatment and prevention ofcancer.

As used herein, “radiotherapy” may consist of gamma-radiation, X-rayradiation, electrons or photons, external radiotherapy or curitherapy.

As used herein, the term “radiotherapeutic agent”, is intended to referto any radiotherapeutic agent known to one of skill in the art to beeffective to treat or ameliorate cancer, without limitation. Forinstance, the radiotherapeutic agent can be an agent such as thoseadministered in brachytherapy or radionuclide therapy. Such methods canoptionally further comprise the administration of one or more additionalcancer therapies, such as, but not limited to, chemotherapies, and/oranother radiotherapy.

According to the invention, the chemotherapeutic agent may be thetemozolomide, 5-aza-2′-deoxycytidine, Theaflavin 3, 3′-digallate,zebularine, decitabine, 4-amino-N-(4-aminophenyl), benzamide analoguesof quinoline-based SGI-1027 (PMID: 24678024 or 23294304.

In one embodiment, the cancer according to the invention is aglioblastoma.

In one embodiment, the invention relates to i) compound according to theinvention, and ii) a chemotherapeutic agent and iii) a radiotherapy, asa combined preparation for simultaneous, separate or sequential for usein the treatment and prevention of glioblastoma.

In a particular embodiment, the invention relates to i) compoundaccording to the invention, and ii) the temozolomide and iii) aradiotherapy, as a combined preparation for simultaneous, separate orsequential for use in the treatment and prevention of glioblastoma.

Typically, the compound according to the invention includes but is notlimited to a small organic molecule, an antibody, an intra-antibody, ananobody and a polypeptide.

In one embodiment, the compound according to the invention may be a lowmolecular weight compound, e. g. a small organic molecule (natural ornot).

The term “small organic molecule” refers to a molecule (natural or not)of a size comparable to those organic molecules generally used inpharmaceuticals. The term excludes biological macromolecules (e. g.,proteins, nucleic acids, etc.). particular small organic molecules rangein size up to about 10000 Da, more particularly up to 5000 Da, moreparticularly up to 2000 Da and most particularly up to about 1000 Da.

In one embodiment, the compound according to the invention is anantibody, an intra-antibody or a nanobody. Antibodies, intra-antibodiesor nanobodies directed against DNMT3A or ISGF3γ proteins can be raisedaccording to known methods by administering the appropriate antigen orepitope to a host animal selected, e.g., from pigs, cows, horses,rabbits, goats, sheep, and mice, among others. Various adjuvants knownin the art can be used to enhance antibody production. Althoughantibodies useful in practicing the invention can be polyclonal ormonoclonal antibodies. Monoclonal antibodies against DNMT3A or ISGF3γproteins can be prepared and isolated using any technique that providesfor the production of antibody molecules by continuous cell lines inculture. Techniques for production and isolation include but are notlimited to the hybridoma technique originally described by Kohler andMilstein (1975); the human B-cell hybridoma technique (Cote et al.,1983); and the EBV-hybridoma technique (Cole et al. 1985).Alternatively, techniques described for the production of single chainantibodies (see e.g., U.S. Pat. No. 4,946,778) can be adapted to produceanti-DNMT3A or anti-ISGF3γ proteins single chain antibodies. Compoundsuseful in practicing the present invention also include anti-DNMT3A oranti-ISGF3γ antibody fragments including but not limited to F(ab′)2fragments, which can be generated by pepsin digestion of an intactantibody molecule, and Fab fragments, which can be generated by reducingthe disulfide bridges of the F(ab′)2 fragments. Alternatively, Faband/or scFv expression libraries can be constructed to allow rapididentification of fragments having the desired specificity to DNMT3A orISGF3γ proteins.

Humanized anti-DNMT3A or anti-ISGF3γ antibodies and antibody fragmentstherefrom can also be prepared according to known techniques. “Humanizedantibodies” are forms of non-human (e.g., rodent) chimeric antibodiesthat contain minimal sequence derived from non-human immunoglobulin. Forthe most part, humanized antibodies are human immunoglobulins (recipientantibody) in which residues from a hypervariable region (CDRs) of therecipient are replaced by residues from a hypervariable region of anon-human species (donor antibody) such as mouse, rat, rabbit ornonhuman primate having the desired specificity, affinity and capacity.In some instances, framework region (FR) residues of the humanimmunoglobulin are replaced by corresponding non-human residues.Furthermore, humanized antibodies may comprise residues that are notfound in the recipient antibody or in the donor antibody. Thesemodifications are made to further refine antibody performance. Ingeneral, the humanized antibody will comprise substantially all of atleast one, and typically two, variable domains, in which all orsubstantially all of the hypervariable loops correspond to those of anon-human immunoglobulin and all or substantially all of the FRs arethose of a human immunoglobulin sequence. The humanized antibodyoptionally also will comprise at least a portion of an immunoglobulinconstant region (Fc), typically that of a human immunoglobulin. Methodsfor making humanized antibodies are described, for example, by Winter(U.S. Pat. No. 5,225,539) and Boss (Celltech, U.S. Pat. No. 4,816,397).

Then, for this invention, neutralizing antibodies of DNMT3A or ISGF3γare selected.

In one embodiment, the compound according to the invention is ananti-DNMT3A antibody.

In a particular embodiment, the antibody according to the invention maybe the ab23565 antibody bought by Abcam or the H-295 antibody bought bySanta Cruz.

In another embodiment, the compound according to the invention is ananti-ISGF3γ antibody.

In one embodiment, the compound according to the invention is anaptamer. Aptamers are a class of molecule that represents an alternativeto antibodies in term of molecular recognition. Aptamers areoligonucleotide or oligopeptide sequences with the capacity to recognizevirtually any class of target molecules with high affinity andspecificity. Such ligands may be isolated through Systematic Evolutionof Ligands by EXponential enrichment (SELEX) of a random sequencelibrary, as described in Tuerk C. and Gold L., 1990. The random sequencelibrary is obtainable by combinatorial chemical synthesis of DNA. Inthis library, each member is a linear oligomer, eventually chemicallymodified, of a unique sequence. Possible modifications, uses andadvantages of this class of molecules have been reviewed in Jayasena S.D., 1999. Peptide aptamers consists of a conformationally constrainedantibody variable region displayed by a platform protein, such as E.coli Thioredoxin A that are selected from combinatorial libraries by twohybrid methods (Colas et al., 1996).

Then, for this invention, neutralizing aptamers of DNMT3A or ISGF3γ areselected.

In one embodiment, the compound according to the invention is a peptide,a polypeptide or a protein.

In a particular embodiment the peptide, the polypeptide or the proteincan be a functional equivalent of DNMT3A or ISGF3γ. As used herein, a“functional equivalent” of DNMT3A or ISGF3γ is a compound which iscapable of binding to DNMT3A or ISGF3γ. The term “functional equivalent”or “function-conservative variants” include fragments, mutants, andmuteins of DNMT3A or ISGF3γ. The term “functionally equivalent” thusincludes any equivalent of DNMT3A or ISGF3γ obtained by altering theamino acid sequence, for example by one or more amino acid deletions,substitutions or additions. Amino acid substitutions may be made, forexample, by point mutation of the DNA encoding the amino acid sequence.

The functional equivalents include soluble forms of DNMT3A or ISGF3γ. Asuitable soluble form of these proteins, or functional equivalentsthereof, might comprise, for example, a truncated form of the proteinfrom which the transmembrane domain has been removed by chemical,proteolytic or recombinant methods.

Particularly, the functional equivalent is at least 80% homologous tothe corresponding protein. In a particular embodiment, the functionalequivalent is at least 90% homologous as assessed by any conventionalanalysis algorithm such as for example, the Pileup sequence analysissoftware (Program Manual for the Wisconsin Package, 1996).

The term “a functionally equivalent fragment” as used herein also maymean any fragment or assembly of fragments of DNMT3A or ISGF3γ.

Functionally equivalent fragments may belong to the same protein familyas the DNMT3A or ISGF3γ identified herein. By “protein family” is meanta group of proteins that share a common function and exhibit commonsequence homology. Homologous proteins may be derived from non-humanspecies. Particularly, the homology between functionally equivalentprotein sequences is at least 25% across the whole of amino acidsequence of the complete protein. More particularly, the homology is atleast 50%, even more particularly 75% across the whole of amino acidsequence of the protein or protein fragment. More particularly, homologyis greater than 80% across the whole of the sequence. More particularly,homology is greater than 90% across the whole of the sequence. Moreparticularly, homology is greater than 95% across the whole of thesequence.

The polypeptides of the invention may be produced by any suitable means,as will be apparent to those of skill in the art. In order to producesufficient amounts of peptide, polypeptide or protein according to theinvention or functional equivalents thereof for use in accordance withthe present invention, expression may conveniently be achieved byculturing under appropriate conditions recombinant host cells containingthe polypeptide of the invention. Particularly, the polypeptide isproduced by recombinant means, by expression from an encoding nucleicacid molecule. Systems for cloning and expression of a polypeptide in avariety of different host cells are well known.

When expressed in recombinant form, the polypeptide may be generated byexpression from an encoding nucleic acid in a host cell. Any host cellmay be used, depending upon the individual requirements of a particularsystem. Suitable host cells include bacteria mammalian cells, plantcells, yeast and baculovirus systems. Mammalian cell lines available inthe art for expression of a heterologous polypeptide include Chinesehamster ovary cells. HeLa cells, baby hamster kidney cells and manyothers. Bacteria are also hosts for the production of recombinantprotein, due to the ease with which bacteria may be manipulated andgrown. A common bacterial host is E. coli.

In specific embodiments, it is contemplated that polypeptides used inthe therapeutic methods of the present invention may be modified inorder to improve their therapeutic efficacy. Such modification oftherapeutic compounds may be used to decrease toxicity, increasecirculatory time, or modify biodistribution. For example, the toxicityof potentially important therapeutic compounds can be decreasedsignificantly by combination with a variety of drug carrier vehiclesthat modify biodistribution. In example adding dipeptides can improvethe penetration of a circulating agent in the eye through the bloodretinal barrier by using endogenous transporters.

A strategy for improving drug viability is the utilization ofwater-soluble polymers. Various water-soluble polymers have been shownto modify biodistribution, improve the mode of cellular uptake, changethe permeability through physiological barriers; and modify the rate ofclearance from the body. To achieve either a targeting orsustained-release effect, water-soluble polymers have been synthesizedthat contain drug moieties as terminal groups, as part of the backbone,or as pendent groups on the polymer chain.

Polyethylene glycol (PEG) has been widely used as a drug carrier, givenits high degree of biocompatibility and ease of modification. Attachmentto various drugs, proteins, and liposomes has been shown to improveresidence time and decrease toxicity. PEG can be coupled to activeagents through the hydroxyl groups at the ends of the chain and viaother chemical methods; however, PEG itself is limited to at most twoactive agents per molecule. In a different approach, copolymers of PEGand amino acids were explored as novel biomaterials which would retainthe biocompatibility properties of PEG, but which would have the addedadvantage of numerous attachment points per molecule (providing greaterdrug loading), and which could be synthetically designed to suit avariety of applications.

Those of skill in the art are aware of PEGylation techniques for theeffective modification of drugs. For example, drug delivery polymersthat consist of alternating polymers of PEG and tri-functional monomerssuch as lysine have been used by VectraMed (Plainsboro, N.J.). The PEGchains (typically 2000 daltons or less) are linked to the a- and e-aminogroups of lysine through stable urethane linkages. Such copolymersretain the desirable properties of PEG, while providing reactive pendentgroups (the carboxylic acid groups of lysine) at strictly controlled andpredetermined intervals along the polymer chain. The reactive pendentgroups can be used for derivatization, cross-linking, or conjugationwith other molecules. These polymers are useful in producing stable,long-circulating pro-drugs by varying the molecular weight of thepolymer, the molecular weight of the PEG segments, and the cleavablelinkage between the drug and the polymer. The molecular weight of thePEG segments affects the spacing of the drug/linking group complex andthe amount of drug per molecular weight of conjugate (smaller PEGsegments provides greater drug loading). In general, increasing theoverall molecular weight of the block co-polymer conjugate will increasethe circulatory half-life of the conjugate. Nevertheless, the conjugatemust either be readily degradable or have a molecular weight below thethreshold-limiting glomular filtration (e.g., less than 60 kDa).

In addition, to the polymer backbone being important in maintainingcirculatory half-life, and biodistribution, linkers may be used tomaintain the therapeutic agent in a pro-drug form until released fromthe backbone polymer by a specific trigger, typically enzyme activity inthe targeted tissue. For example, this type of tissue activated drugdelivery is particularly useful where delivery to a specific site ofbiodistribution is required and the therapeutic agent is released at ornear the site of pathology. Linking group libraries for use in activateddrug delivery are known to those of skill in the art and may be based onenzyme kinetics, prevalence of active enzyme, and cleavage specificityof the selected disease-specific enzymes. Such linkers may be used inmodifying the protein or fragment of the protein described herein fortherapeutic delivery.

In one embodiment, the peptide of the invention is the peptide P1 (SEQID NO:1).

Thus, the invention also relates to a peptide comprising the amino acidssequence: RPMPRLTFQAGDPYYI (SEQ ID NO:1) or a function-conservativevariant thereof.

Thus, the peptide comprising the amino acids sequence SEQ ID NO: 1 or afunction-conservative variant may be used for treating or preventingcancer.

Thus according to a particular embodiment, the invention relates to i) acompound which is the peptide P1 (SEQ ID NO:1) or afunction-conservative variant thereof, and ii) the temozolomide, as acombined preparation for simultaneous, separate or sequential for use inthe treatment and prevention of cancer.

Thus according to a particular embodiment, the invention relates to i) acompound which is the peptide P1 (SEQ ID NO:1) or afunction-conservative variant thereof, and ii) the temozolomide, as acombined preparation for simultaneous, separate or sequential for use inthe treatment and prevention of glioblastoma.

Thus according to a particular embodiment, the invention relates to i) acompound which is the peptide P1 (SEQ ID NO:1), and ii) the temozolomideand iii) a radiotherapy, as a combined preparation for simultaneous,separate or sequential for use in the treatment and prevention ofcancer.

Thus according to a particular embodiment, the invention relates to i) acompound which is the peptide P1 (SEQ ID NO:1), and ii) the temozolomideand iii) a radiotherapy, as a combined preparation for simultaneous,separate or sequential for use in the treatment and prevention ofglioblastoma.

In one embodiment, the compound is a functionally equivalent fragment ofthe peptide P1.

In one embodiment, the peptide P1 of SEQ ID NO:1 is used to sensitivecancer cell to a chemotherapeutic agent and particularly totemozolomide.

P1: SEQ ID NO: 1: RPMPRLTFQAGDPYYI P1mut: SEQ ID NO: 2: RPMPRLTAQAGAPYYI

In a particular embodiment, the invention relates to a peptidecomprising the amino acids sequence SEQ ID NO:1 or afunction-conservative variant thereof.

The invention also encompasses peptides that are function-conservativevariants of the peptide comprising SEQ ID NO: 1 as described here above.

In one embodiment, the peptide according to the invention may differfrom 1, 2 or 3 amino acids to the SEQ ID NO:1.

In another embodiment, the peptide according to the invention may differfrom 4 or 5 amino acids to the SEQ ID NO:1.

In one embodiment, the peptide of the invention comprises at least 75%identity over said the SEQ ID NO: 1, even more preferably at least 80%,at least 85%, at least 90%, at least 95%, at least 97% and is still ableto decrease tumor cell proliferation or still able to induce PCD intumor cell.

In one embodiment, the peptide of the invention consists in the aminoacid sequence as set forth in SEQ ID NO:1 or a variant thereofcomprising at least 75%, preferably at least 80%, 85%, 90%, 95%, 96%,97%, 98%, 99%, 99.5% or 99.9% identity with SEQ ID NO:1 and is stillable for disrupting the DNMT3A/ISGF3γ interaction.

To verify whether the newly generated peptides induce a disruption ofthe DNMT3A/ISGF3γ interaction, a test as described above can beperformed.

In one embodiment of the invention, said peptide is an amino acidsequence of less than 50 amino acids long that comprises the amino acidsequence SEQ ID NO:1 as defined here above.

In another embodiment of the invention, said soluble peptide is an aminoacid sequence of less than 45 amino acids long that comprises the aminoacid sequence SEQ ID NO:1 as defined here above.

In another embodiment of the invention, said soluble peptide is an aminoacid sequence of less than 40 amino acids long that comprises the aminoacid sequence SEQ ID NO:1 as defined here above.

In another embodiment of the invention, said soluble peptide is an aminoacid sequence of less than 30 amino acids long that comprises the aminoacid sequence SEQ ID NO:1 as defined here above.

In another embodiment of the invention, said soluble peptide is an aminoacid sequence of less than 20 amino acids long that comprises the aminoacid sequence SEQ ID NO:1 as defined here above.

In another embodiment of the invention, said soluble peptide is an aminoacid sequence of less than 15 amino acids long that comprises the aminoacid sequence SEQ ID NO:1 as defined here above.

In some embodiments the peptide, the polypeptide or the protein of theinvention and particularly the peptide P1 is linked with at least onecell penetrating peptide (CPP).

The terms “cell penetrating peptide” or “CPP” are used interchangeablyand refer to cationic cell penetrating peptides, also called transportpeptides, carrier peptides, or peptide transduction domains. The CPP, asshown herein, have the capability of inducing cell penetration of apeptide fused to the CPP within 30%, 40%, 50%, 60%, 70%, 80%, 90%, or100% of cells of a given cell culture population, including all integersin between, and allow macromolecular translocation within multipletissues in vivo upon systemic administration. A cell-penetrating peptidemay also refer to a peptide which, when brought into contact with a cellunder appropriate conditions, passes from the external environment inthe intracellular environment, including the cytoplasm, organelles suchas mitochondria, or the nucleus of the cell, in conditions significantlygreater than passive diffusion. Such penetrating peptides may be thosedescribed in Fonseca S. B. et al., Advanced Drug Delivery Reviews, 2009,61: 953-964, Johansson et al., Methods in Molecular Biology, 2011, Vol.683, Chapter 17, Bechara and Sagan, (2013) FEBS letters 587, 1693-1702.;Jones and Sayers (2012), Journal of controlled release: official journalof the Controlled Release Society 161, 582-591; Khafagy el andMorishita, (2012) Advanced drug delivery reviews 64, 531-539; Malhi andMurthy, (2012) Expert opinion on drug delivery 9, 909-935, inWO2004/011595 and in WO2003/011898. All that CPP are incorporated byreference.

In a particular embodiment, the cell penetrating peptide comprises orconsists of: Tat peptide, polyarginines peptide, HA2-R9 peptide,Penetratin peptide, Transportan peptide, Vectocell® peptide,maurocalcine peptide, decalysine peptide, HIV-Tat derived PTD4 peptide,Hepatitis B virus Translocation Motif (PTM) peptide, mPrP1-28 peptide,POD, pVEC, EB1, Rath, CADY, Histatin 5, Antp peptide, Cyt86-101 peptide,DPT peptide.

In another particular embodiment, the peptide, the polypeptide or theprotein of the invention is linked to two, three or more penetratingpeptides.

In another embodiment, the compound according to the invention is aninhibitor of DNMT3A or ISGF3γ gene expression.

Small inhibitory RNAs (siRNAs) can also function as inhibitors of DNMT3Aor ISGF3γ expression for use in the present invention.

DNMT3A or ISGF3γ gene expression can be reduced by contacting a subjector cell with a small double stranded RNA (dsRNA), or a vector orconstruct causing the production of a small double stranded RNA, suchthat DNMT3A or ISGF3γ gene expression is specifically inhibited (i.e.RNA interference or RNAi). Methods for selecting an appropriate dsRNA ordsRNA-encoding vector are well known in the art for genes whose sequenceis known (e.g. see for example Tuschl, T. et al. (1999); Elbashir, S. M.et al. (2001); Hannon, G J. (2002); McManus, M T. et al. (2002);Brummelkamp, T R. et al. (2002); U.S. Pat. Nos. 6,573,099 and 6,506,559;and International Patent Publication Nos. WO 01/36646, WO 99/32619, andWO 01/68836).

In one embodiment, miRNA can be used to as inhibitors of DNMT3A orISGF3γ gene expression. For example, miRNA-29a and b, miRNA-143,miRNA-101 and miRNA 369 can be used to inhibit DNMT3A gene expressionand miRNA-106 can be used to inhibit ISGF3G gene expression.

Ribozymes can also function as inhibitors of DNMT3A or ISGF3γ geneexpression for use in the present invention. Ribozymes are enzymatic RNAmolecules capable of catalyzing the specific cleavage of RNA. Themechanism of ribozyme action involves sequence specific hybridization ofthe ribozyme molecule to complementary target RNA, followed byendonucleolytic cleavage. Engineered hairpin or hammerhead motifribozyme molecules that specifically and efficiently catalyzeendonucleolytic cleavage of DNMT3A or ISGF3γ mRNA sequences are therebyuseful within the scope of the present invention. Specific ribozymecleavage sites within any potential RNA target are initially identifiedby scanning the target molecule for ribozyme cleavage sites, whichtypically include the following sequences, GUA, GUU, and GUC. Onceidentified, short RNA sequences of between about 15 and 20ribonucleotides corresponding to the region of the target genecontaining the cleavage site can be evaluated for predicted structuralfeatures, such as secondary structure, that can render theoligonucleotide sequence unsuitable. The suitability of candidatetargets can also be evaluated by testing their accessibility tohybridization with complementary oligonucleotides, using, e.g.,ribonuclease protection assays.

Both antisense oligonucleotides and ribozymes useful as inhibitors ofDNMT3A or ISGF3γ gene expression can be prepared by known methods. Theseinclude techniques for chemical synthesis such as, e.g., by solid phasephosphoramadite chemical synthesis. Alternatively, anti-sense RNAmolecules can be generated by in vitro or in vivo transcription of DNAsequences encoding the RNA molecule. Such DNA sequences can beincorporated into a wide variety of vectors that incorporate suitableRNA polymerase promoters such as the T7 or SP6 polymerase promoters.Various modifications to the oligonucleotides of the invention can beintroduced as a means of increasing intracellular stability andhalf-life. Possible modifications include but are not limited to theaddition of flanking sequences of ribonucleotides ordeoxyribonucleotides to the 5′ and/or 3′ ends of the molecule, or theuse of phosphorothioate or 2′-O-methyl rather than phosphodiesteraselinkages within the oligonucleotide backbone.

Antisense oligonucleotides siRNAs and ribozymes of the invention may bedelivered in vivo alone or in association with a vector. In its broadestsense, a “vector” is any vehicle capable of facilitating the transfer ofthe antisense oligonucleotide siRNA or ribozyme nucleic acid to thecells and particularly cells expressing DNMT3A or ISGF3γ. Particularly,the vector transports the nucleic acid to cells with reduced degradationrelative to the extent of degradation that would result in the absenceof the vector. In general, the vectors useful in the invention include,but are not limited to, plasmids, phagemids, viruses, other vehiclesderived from viral or bacterial sources that have been manipulated bythe insertion or incorporation of the the antisense oligonucleotidesiRNA or ribozyme nucleic acid sequences. Viral vectors are a particulartype of vector and include, but are not limited to nucleic acidsequences from the following viruses: retrovirus, such as moloney murineleukemia virus, harvey murine sarcoma virus, murine mammary tumor virus,and rouse sarcoma virus; adenovirus, adeno-associated virus; SV40-typeviruses; polyoma viruses; Epstein-Barr viruses; papilloma viruses;herpes virus; vaccinia virus; polio virus; and RNA virus such as aretrovirus. One can readily employ other vectors not named but known tothe art.

Particular viral vectors are based on non-cytopathic eukaryotic virusesin which non-essential genes have been replaced with the gene ofinterest. Non-cytopathic viruses include retroviruses (e.g.,lentivirus), the life cycle of which involves reverse transcription ofgenomic viral RNA into DNA with subsequent proviral integration intohost cellular DNA. Retroviruses have been approved for human genetherapy trials. Most useful are those retroviruses that arereplication-deficient (i.e., capable of directing synthesis of thedesired proteins, but incapable of manufacturing an infectiousparticle). Such genetically altered retroviral expression vectors havegeneral utility for the high-efficiency transduction of genes in vivo.Standard protocols for producing replication-deficient retroviruses(including the steps of incorporation of exogenous genetic material intoa plasmid, transfection of a packaging cell lined with plasmid,production of recombinant retroviruses by the packaging cell line,collection of viral particles from tissue culture media, and infectionof the target cells with viral particles) are provided in Kriegler, 1990and in Murry, 1991).

Particular viruses for certain applications are the adeno-viruses andadeno-associated viruses, which are double-stranded DNA viruses thathave already been approved for human use in gene therapy. Theadeno-associated virus can be engineered to be replication deficient andis capable of infecting a wide range of cell types and species. Itfurther has advantages such as, heat and lipid solvent stability; hightransduction frequencies in cells of diverse lineages, includinghemopoietic cells; and lack of superinfection inhibition thus allowingmultiple series of transductions. Reportedly, the adeno-associated viruscan integrate into human cellular DNA in a site-specific manner, therebyminimizing the possibility of insertional mutagenesis and variability ofinserted gene expression characteristic of retroviral infection. Inaddition, wild-type adeno-associated virus infections have been followedin tissue culture for greater than 100 passages in the absence ofselective pressure, implying that the adeno-associated virus genomicintegration is a relatively stable event. The adeno-associated virus canalso function in an extrachromosomal fashion.

Other vectors include plasmid vectors. Plasmid vectors have beenextensively described in the art and are well known to those of skill inthe art. See e.g. Sambrook et al., 1989. In the last few years, plasmidvectors have been used as DNA vaccines for delivering antigen-encodinggenes to cells in vivo. They are particularly advantageous for thisbecause they do not have the same safety concerns as with many of theviral vectors. These plasmids, however, having a promoter compatiblewith the host cell, can express a peptide from a gene operativelyencoded within the plasmid. Some commonly used plasmids include pBR322,pUC18, pUC19, pRC/CMV, SV40, and pBlueScript. Other plasmids are wellknown to those of ordinary skill in the art. Additionally, plasmids maybe custom designed using restriction enzymes and ligation reactions toremove and add specific fragments of DNA. Plasmids may be delivered by avariety of parenteral, mucosal and topical routes. For example, the DNAplasmid can be injected by intramuscular, eye, intradermal,subcutaneous, or other routes. It may also be administered by intranasalsprays or drops, rectal suppository and orally. It may also beadministered into the epidermis or a mucosal surface using a gene-gun.The plasmids may be given in an aqueous solution, dried onto goldparticles or in association with another DNA delivery system includingbut not limited to liposomes, dendrimers, cochleate andmicroencapsulation.

In a particular embodiment, the antisense oligonucleotide, siRNA, shRNAor ribozyme nucleic acid sequence is under the control of a heterologousregulatory region, e.g., a heterologous promoter. The promoter may bespecific for Muller glial cells, microglia cells, endothelial cells,pericyte cells and astrocytes For example, a specific expression inMuller glial cells may be obtained through the promoter of the glutaminesynthetase gene is suitable. The promoter can also be, e.g., a viralpromoter, such as CMV promoter or any synthetic promoters.

Another object of the invention relates to a method for treating andpreventing cancer comprising administrating to a subject in need thereofa therapeutically effective amount of a compound which is aDNMT3A/ISGF3γ antagonist or a compound which is a DNMT3A/ISGF3γ geneexpression inhibitor.

In one embodiment, the invention relates to a method for treating andpreventing glioblastoma comprising administrating to a subject in needthereof a therapeutically effective amount of a compound which is aDNMT3A/ISGF3γ antagonist or a compound which is a DNMT3A/ISGF3γ geneexpression inhibitor.

Therapeutic Composition

Another object of the invention relates to a therapeutic compositioncomprising a compound according to the invention for use in thetreatment and prevention of cancer.

In one embodiment, the invention relates to a therapeutic compositioncomprising a compound according to the invention for use in thetreatment and prevention of glioblastoma

Any therapeutic agent of the invention may be combined withpharmaceutically acceptable excipients, and optionally sustained-releasematrices, such as biodegradable polymers, to form therapeuticcompositions.

“Pharmaceutically” or “pharmaceutically acceptable” refers to molecularentities and compositions that do not produce an adverse, allergic orother untoward reaction when administered to a mammal, especially ahuman, as appropriate. A pharmaceutically acceptable carrier orexcipient refers to a non-toxic solid, semi-solid or liquid filler,diluent, encapsulating material or formulation auxiliary of any type.

The form of the pharmaceutical compositions, the route ofadministration, the dosage and the regimen naturally depend upon thecondition to be treated, the severity of the illness, the age, weight,and sex of the patient, etc.

The pharmaceutical compositions of the invention can be formulated for atopical, oral, intranasal, parenteral, intraocular, intravenous,intramuscular or subcutaneous administration and the like.

Particularly, the pharmaceutical compositions contain vehicles which arepharmaceutically acceptable for a formulation capable of being injected.These may be in particular isotonic, sterile, saline solutions(monosodium or disodium phosphate, sodium, potassium, calcium ormagnesium chloride and the like or mixtures of such salts), or dry,especially freeze-dried compositions which upon addition, depending onthe case, of sterilized water or physiological saline, permit theconstitution of injectable solutions.

The doses used for the administration can be adapted as a function ofvarious parameters, and in particular as a function of the mode ofadministration used, of the relevant pathology, or alternatively of thedesired duration of treatment.

In addition, other pharmaceutically acceptable forms include, e.g.tablets or other solids for oral administration; time release capsules;and any other form currently can be used.

Pharmaceutical compositions of the present invention may comprise afurther therapeutic active agent. The present invention also relates toa kit comprising a compound according to the invention and a furthertherapeutic active agent.

In one embodiment said therapeutic active agent may be an anti-canceragent.

The invention will be further illustrated by the following figures andexamples. However, these examples and figures should not be interpretedin any way as limiting the scope of the present invention.

FIGURES

FIG. 1. A high level of DNMT3A/ISGF3γ interaction is a poor prognosisfactor.

Kaplan-Meier curves illustrate the difference of overall survival (OS)between patient with high (H) and low (L) levels of DNMT3A/ISGF3γinteraction. p value is obtained by performing a Cox ProportionalHazards Survival Regression test.

FIG. 2. Specific disruption of DNMT3a/ISGF3γ interaction.

A and B. Impact of peptides miming the DNMT3A/ISGF3γ binding regions onthe DNMT3A/ISGF3γ interaction. Pictures and graphs are representativesof three independent pull-down experiments. I: input. p values wereobtained by performing a t test.

FIG. 3. Effect of a treatment associating the P1 peptide with TMZ in aswiss nude mice model of established tumors.

A. Design of the experiment. Tumor establishment indicates that 2.106PCTC-GBM were injected to form a tumor of which the volume was equal to100 mm3±33.3. Then, mice were treated with indicated treatment. D: day,w: week, it: intra-tumoral, ip: Intraperitoneal.

B. Graph illustrates the impact of the 4 considered treatments on tumorweight of established tumors. Open circles represent mice. Black circlesrepresent the average±standard deviation obtained for each treatment. pvalues were obtained by performing a t test.

EXAMPLE

Material & Methods

Patient Characteristics.

Overall survival was measured from the date of surgical resection to thedeath. In each tumor grade, all patients included in this study hadsimilar management and similar treatment (including temozolomide (TMZ)for GBM). Patient material as well as records (diagnosis, age, sex, dateof death, Karnofsky performance score (KPS)) was used withconfidentiality according to French laws and recommendations of theFrench National Committee of Ethic.

Primary Cultured Tumor Cells (PCTC).

Fresh brain tumor tissues obtained from the neurosurgery service of theLaennec Hospital (Nantes/Saint-Herblain, France) were collected andprocessed within 30 min after resection. The clinical protocol wasapproved by the French laws of ethics with informed consent obtainedfrom all subjects. The primary cultured tumor cells were obtained aftermechanical dissociation according to the technique previously described.Briefly, tumor tissue was cut into pieces of 1-5 mm3 and plated in a 60mm2 tissue culture dish with DMEM with 10% FBS and antibiotics.Additionally and in parallel, minced pieces of tumor were incubated with200 U/ml collagenase I (Sigma, France) and 500 U/ml DNaseI (Sigma,France) in PBS during 1 hr at 37° C. with vigorous constant agitation.The single-cell suspension was filtered through a 70 mm cell strainer(BD Falcon, France), washed with PBS, and suspended in DMEM-10% FBS.Cell cultures were subsequently split 1:2 when confluent and experimentswere done before passage 3-5.

Proximity Ligation In Situ Assay (P-LISA).

Cells were cultured for 24 h on cover slip. Cells were then fixed with4% paraformaldehyde in PBS pH7.4 for 15 min at room temperature.Permeabilization is performed with PBS containing 0.5% Triton X-100 for20 min at room temperature. Blocking, staining, hybridization, ligation,amplification and detection steps were realized according tomanufacturer's instructions (Olink Bioscience, Sweden). All incubationswere performed in a humidity chamber. Amplification and detection stepswere performed in dark room. Fluorescence was visualized by using theAxiovert 200M microscopy system (Zeiss, Le Pecq, France) with ApoTomemodule (X63 and numerial aperture 1.4). Preparations were mounted byusing ProLong Gold antifade reagent with DAPI (Life Technologies,France). Pictures acquisition was realized in structured illuminationmicroscopy. After decovolving (3.5 Huygens Essential software (SVI)), 3Dview was obtained by using Amira.4.1.1 program. Finally, the images wereanalyzed by using the freeware “BlobFinder” available for download fromwww.cb.uu.se/˜amin/BlobFinder. Thus, we obtained either number ofsignals per nuclei since nuclei can be automatically identified.

Epitope Mapping.

Peptides were spotted on an Amino-PEG500-UC540 membrane using a MultiPeppeptide synthesizer (Intavis AG, Cologne, Germany) at a loading capacityof 400 nmol/cm2. After synthesis the membrane was dried then the cappedside-chains were deprotected by cleavage for 1 h with a cocktailcontaining 95% trifluoroacetic acid, 3% tri-isopropyl, 2% H2O. Thetrifluoroacetic acid was removed and the membrane rinsed withdichloromethane, followed by dimethylformaldehyde and then ethanol. Themembrane was saturated before incubation with the considered recombinantprotein for 2 h at room temperature. After which, it was washed threetimes, positive peptides were revealed using antibodies coupled to afluorochrome. Typhoon (GE Healthcare, France) was used to determinefluorescence. The binding intensities of the considered recombinantprotein for the spotted peptides were determined by quantification usingImageJ software and converted to sequence-specific normalized units. Theintensities obtained for each peptide covering a given amino acid wereadded and divided by the number of peptides.

Pull-Down Assay.

Pull-down assays were performed by using the GST/His Tagged-ProteinInteraction Pull-Down Kits (Thermo Scientific, France). Briefly, 100 μgof bait protein were immobilized on column via an incubation at 4° C.for 1 h with gentle mixing. After washing, 1 μg of prey protein wasadded for 1 h at 4° C. with gentle rocking motion on a rotatingplatform. After washes and elution, the “bait-prey” interaction wasanalyzed by SDS-PAGE and Western blot methods. Competitive pull-downexperimentations were realized by pre-incubating considered peptides for1 h at 37° C.

Western Blot Analysis.

In brief, proteins were size fractionated by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Proteins were transferredonto nitrocellulose or PVDF membrane. Saturation and blotting wererealized by using SNAP i.™ Protein Detection System (Millipore, France).The detection of proteins was performed using ECL™ (AmershamBiosciences, France) and/or SuperSignal west femto Maximum Sensitivity(Thermo Scientific, France) chemilumenscence reagents. The detection ofproteins was performed using the FusionX7 Imager (Fisher Scientific,France).

Transfer of Peptides into Cells Via Electroporation.

For electroporation, NLS sequence was added to peptides. Cells wereharvested during the exponential growth phase by trypsinization and wereresuspended in their original media. They were washed in PBS, pH 7.2(0.14 M NaCl, 2 mM KCl, 8 mM Na2HPO4 and 1.5 mM NaH2PO4) and resuspendedat a concentration of 0.6×106 cells/ml in original culture medium. Next,0.8 ml of the cell suspension was mixed with the peptides (50 μg/ml),allowed to stand at room temperature for 10 min and added to adisposable 0.4 cm Bio-Rad electroporation cuvette (Bio-Rad, France). Anequivalent volume of DMSO was added to a cell suspension without peptidefor use as a control (also named untreated). Electroporation efficiencyfor each cell line was initially determined by flow cytometry by uptakeof the fluorescent dye, lucifer yellow (Sigma, France). Electroporationwas carried out in a Gene-Pulser (Bio-Rad, France) with cells exposed toone pulse. The following parameters were used: cuvette gap 0.4 cm,voltage 0.3 kV, time constant 35 ms, and capacitor 960 μF. Followingelectroporation, cells were allowed to recover by standing at roomtemperature for 10 min, then removed from the electroporation chamber,washed twice in PBS and resuspended in 2 ml of original culture medium.

Measure of Global DNA Methylation.

DNA was extracted by using the QiaAmp DNA mini Kit (Qiagen, France).Next, global DNA methylation was estimated by quantifying the presenceof 5-methylcytosine using Methylamp Global DNA methylationQuantification kit (Euromedex-Epigentek, France) according to themanufacturers's instructions.

Measure of Cell Death.

Percentages of cell death were evaluated by using a Trypan Blue Stain0.4%, and the Countess® Automated Cell Counter (Life Technologies,France). Cell death was induced using temozolomide (25 μM) andirradtiation (2 Gy) such as previously described.

Proliferation Assay and Doubling Time.

Doubling time (i.e. the period of time required for a quantity to doublein size) was calculated by using the Doubling Time Online Calculatorwebsite (Roth V. 2006, http://www.doubling-time.com/compute.php) andcounting the proliferation of 103 cells over 120 hours. Cell number wasdetermined, every 24 h over 120 h, using the Countess® Automated CellCounter (Life Technologies, France).

Migration Assay—Scratch Test.

Cell migration assay was performed using a scratch technique. Cells wereplated in 6-well plates at 80-90%, and were treated with 10 μg/mlmitomycin C (Sigma, Farnce) for 2 hours (in order to remove theinfluence of cell proliferation). Cells were then scratched. Cellmigration was monitored by microscopy. The images acquired for eachsample were analyzed quantitatively. For each image, distances betweenone side of scratch and the other were measured. By comparing the imagesfrom time 0 to the last time point (24 hours), we obtain the distance ofeach scratch closure on the basis of the distances that are measured.

Invasion Assay.

All of the procedures were followed according to the manufacturer'sinstructions (QCM 24-Well Collagen-Based Cell Invasion Assay, Millipore,France). In brief, 200 μl serum-free medium containing 2×105 cells wereseeded into the invasion chamber and placed into the 24 well platecontaining 500 μl complete medium. After 72 h incubation at 37° C.,media was removed from the chamber, and cells were stained by puttingthe chamber in staining solution for 20 min at room temperature.Non-invaded cells were carefully removed from the top-side of thechamber. Stained chamber was inserted into a clean well containing 200μl of extraction buffer for 15 min at room temperature. 100 μl extractedstained solution from the chamber was transferred into the 96 well plateand optical density was measured at 560 nm with a spectrophotometer.

Tumorigenicity Assay.

Cultured cells were harvested by trypsinization, washed and resuspendedin saline buffer. Cell suspensions were injected s.c. as 2.106 cells in0.05 ml of PBS with equal volume of matrigel matrix (Becton Dickinson,France) in the flank of 7/8-week-old Nude NMRI-nu female mice (Janvier,France). After tumor establishment, mice were treated with temozolomideand/or peptides via intra-tumor injection (it). To obtain tumor weigh,each tumor was surgically removed and is weighed. All experimentalprocedures using animals were realized in accordance with the guidelinesof Institutional Animal Care and the French National Committee ofEthics.

Statistical Analysis.

All experiments were done at least in triplicates. Significance of thedifferences in means was calculated using Student-t test. Survivalcurves were plotted according to Kaplan-Meier method and compared by theCox proportional hazards survival regression analysis (such as indicatedon the corresponding figures). Significance of correlation between twoparameters was calculated using Pearson's test.

Results

A High Level of DNMT3A/ISGF3γ Interaction Correlates with a Poor Levelof Sensitivity to Temozolomide/Irradiation-Induced Cell Death.

To determine whether the presence of interaction between DNMT3A and aDNMT3A-binding protein (D3ABP) could permit to identify a subpopulationof GBM patients whose the glioma cells harbor a phenotype of resistanceto the temozolomide/irradiation treatment, we have established 31primary cultured tumor cells (PCTCs) from patient-derived biopsies.Then, these PCTC were used to evaluate the putative correlation betweenthe number of certain DNMT3A/D3A-BP interactions and thetemozolomide/irradiation-induced (TMZ/IR-induced) cell death percentage(data not shown). In our study, we focused on the DNMT3A/HDAC1,DNMT3A/AP2α, DNMT3A/GATA1 and DNMT3A/ISGF3γ interaction since we andother have already demonstrated their existence [Fuks F et al., 2001 andHervouet E et al., 2009]. Proximity Ligation In Situ Assay (P-LISA) wasused to monitor the interaction of interest. The TMZ/IR-induced celldeath percentage was estimated by using trypan blue method (data notshown). The number of DNMT3A/D3A-BP interactions of interest and theTMZ/IR-induced cell death percentage were plotted against each other(data not shown). Statistical analysis using Pearson's correlation testshowed a significant and inverse correlation only between the number ofDNMT3A/ISGF3γ interactions and the TMZ/IR-induced cell death percentage(p=0.002) (data not shown). These results suggested that DNMT3A/ISGF3γcould play a crucial role in the poor response prognosis of glioma cellsto the TMZ/IR treatment.

A High Level of DNMT3A/ISGF3γ Interaction is a Poor Prognosis Factor.

The 31 patients were divided into two groups based on the DNMT3A/ISGF3γinteraction levels found on their tumor biopsies. Tumors from 15patients expressed high levels of DNMT3A/ISGF3γ interaction (higher thanthe median of DNMT3A/ISGF3γ interaction, 12.5), while 16 patients had aDNMT3A/ISGF3γ interaction equal to or lower than 12.5. Overall survivalcurves were estimated by the Kaplan-Meier method and compared with theCox Proportional Hazards Survival Regression Analysis (FIG. 1). Asignificant difference was observed in overall survival (p=0.0092)between patients whose tumors had high levels of DNMT3A/ISGF3γinteraction and those whose tumors did not. These data indicate that ahigh level of DNMT3A/ISGF3γ interaction is a poor prognosis factor.

Specific Disruption of DNMT3A/ISGF3γ Interaction.

The double fact that high level of DNMT3a/ISGF3γ interaction wasassociated with a poor response prognosis to thetemozolomide/irradiation treatment and was associated with of poorprognosis of overall survival, suggest that DNMT3A/ISGF3γ interactioncould be used as a therapeutic target.

To develop a therapeutic strategy aiming to inhibit the DNMT3A/ISGF3γinteraction, we performed a set of experiments aiming to characterizethe DNMT3A/ISGF3γ interaction. In this set of experiments, epitopemapping analysis was performed to identify the amino acids region ofDNMT3A interaction with ISGF3γ. Thus, the primary sequence of DNMT3A wasdecomposed into 12-mer peptides overlapping by 10 residues covalentlybound to a nitrocellulose membrane. Two negative controls were performedto observe that neither the incubation of GST protein (2 μg) nor the useof antibodies against ISGF3γ induced the detection of positive peptides(data not shown). Then, 2 μg of GST-ISGF3γ protein were incubated withthe membrane. The positive peptides for an interaction with GST-ISGF3γwere then detected by using Thyphoon and antibodies directed againstISGF3γ (data not shown). After fluorescence quantification, thesequences of amino acids of DNMT3A interacting with GST-ISGF3γ weredetermined (data not shown). Thus, we observed that the sequences 85-99,103-129, 178-207, 235-246, 256-273, 331-360, 409-433 and 547-574 of theDNMT3A protein sequence were implicated in the DNMT3A/ISGF3γinteraction.

To validate the implication of these amino acid domains on theDNMT3A/ISGF3γ interaction, we derived peptides from these domains inorder to test the ability of these peptides to inhibit the DNMT3A/ISGF3γinteraction in a pull-down assay (data not shown). We thus noted thatonly P1 (RPMPRLTFQAGDPYYI, SEQ ID NO:1) inhibited the DNMT3A/ISGF3γinteraction (FIG. 2A). The efficiency of P1 to inhibit the DNMT3A/ISGF3γinteraction was also reinforced by the fact that 1) a mutated P1 peptide(P1^(mut), RPMPRLTAQAGAPYYI, SEQ ID NO:2) does not inhibit theDNMT3A/ISGF3γ interaction (FIG. 2A) and 2) DNMT3A/ISGF3γ interactiondecreased in presence of increasing concentration of P1 peptide (FIG.2B).

Proximity Ligation In Situ Assays (P-LISA) were next used to monitor theDNMT3A/ISGF3γ interactions in cells. For these experiments, we used aPCTC (named PCTC#1). Electroporation was used to transfect P1 in cells.P-LISA were performed 12 hr after electroporation. Thus, we noted thatred dots representing the DNMT3A/ISGF3γ interactions decreased whencells were treated with the P1 and not in presence of P1^(mut) (data notshown).

All these results indicated that P1 peptide induced the disruption ofDNMT3A/ISGF3γ interactions.

Specific Effect of P1 Peptide.

P1 was designed to inhibit the DNMT3A/ISGF3γ interactions. However, P1could also affect other interaction existing between DNMT3 and a D3A-BP.To investigate this point, we analyzed the effect of P1 on theDNMT3A/D3A-BP interactions of interest. We noted that P1 has no effecton the integrity of the DNMT3A/GATA1, DNMT3A/AP2γ and DNMT3A/HDAC1interactions in PCTC#1.

The analysis of all interactions being impossible, we postulated that ifP1 inhibited a large number of DNMT3A/D3A-BP interactions, anhypomethylation phenotype would be observable. To observe the putativeP1-induced DNA hypomethylation, PCTC#1 were treated during 30 days withP1 (data not shown). Other DNMT inhibitors (5-aza-2-deoxycytidine(5-aza), theaflavin 3,3 digallate (a DNMT3A inhibitor, hereafter calledTFD), or peptides (UP peptide, a peptide inhibiting the DNMT1/PCNA/UHRF1interactions)) were also used as control conditions. ELISA monitoringthe global level of 5-methylcytosine revealed that P1 had not effect onthe global level of 5-methylcytosine, while the 5-aza, TFD and UPtreatments decreased the global level of DNA methylation (data notshown).

Based on these data, we conclude that P1 seems to be specific fordisrupting the DNMT3A/ISGF3γ interaction and without promoting globalDNA hypomethylation.

Impact of P1 Peptide on Cancer Hallmarks/Phenotypes.

We then determined the impact of the P1-induced disruption of theDNMT3A/ISGF3γ interactions on several cancer hallmarks/phenotypesincluding proliferation level, invasion, migration and evasion ofapoptosis (or more particularly the sensitivity of apoptosis induced bya therapeutic treatment). For this purpose, cells were treated by P1 andTDF such as previously described.

To evaluate the impact of the P1-induced disruption of the DNMT3A/ISGF3γinteractions on the sensitivity of apoptosis induced by a therapeutictreatment, we measured the percentage oftemozolomide+irradiation-induced cell death since temozolomide (TMZ) andirradiation are conjugated in anti-GBM treatment [Cheray M et al., 2013and Louis D et al., 2007]. Results show that the percentage of celldeath of P1 and TDF treated cells increased, and the percentage of celldeath of P1 treated cells was higher than the one obtained with TDF.Thus, we conclude that P1 acts as a sensitizer of thetemozolomide+irradiation-induced cell death.

To estimate the impact of the P1-induced disruption of DNMT3A/ISGF3γinteractions on proliferation, we calculated the doubling time. We foundthat both P1 and TFD treatments have no effect on the doubling time ofcells (data not shown).

Impact of the P1-induced disruption of the DNMT3A/ISGF3γ interactions onmigration capability was next estimated by performing a scratch testassay. Results indicate that P1 treatment decreased cell migration whileTFD treatments had no effect on cell migration.

Impact of the P1 and TFD treatments on cell invasion was next estimatedby performing a collagen-based cell invasion assay. results indicatethat P1 unmodified the cell invasion characteristic, while TDF treatmentpromoted the cell invasion.

To summarize these data, we created and calculated the Score ofModulation of Cancer Hallmarks (SMoCH) by attributing −1 when thepeptide/treatment enhanced a cancer hallmark, 0 when peptide/treatmentdid not modify a cancer hallmark and +1 when the peptide/treatmentinhibited a cancer hallmark. Thus, a positive SMoCH suggests that theconsidered peptide/treatment inhibits more cancer hallmarks than itpromotes them, so the benefit/risk balance is favorable for using theconsidered peptide/treatment in anticancer therapy. Results indicatingthat P1 treatment is in this situation, we concluded that P1 treatmentcould be efficient in anti-cancer therapy.

Effect of a Treatment Associating P1 Peptide with TMZ in a Swiss NudeMice Model of Established Tumors.

Standard anti-GBM treatment using temozolomide as chemotherapeuticagent, we next investigated the effect of a treatment associating P1peptide with TMZ in a swiss nude mice model of established tumors. Forthis purpose, 16 swiss Nude mice were injected subcutaneously by 2.10⁶glioma cells (having high level of DNMT3A/ISGF3γ interactions (FIG. 3A).Next, when the tumor volume was equal to 100 mm³, 4 mice were randomlyuntreated, treated with TMZ, TMZ+P1, TMZ+P1^(mut) or P1 (called T1 andT5 respectively). After 3 weeks of treatment, we noted that TMZtreatment was inefficient to limit tumor growth since no statisticaldifference was observed between untreated mice and mice treated with TMZonly, and between untrated mice and mice treated with P1 (FIG. 3B). Moreinterestingly, we noted that the TMZ+P1 treatment reduced tumorsvolumes, while the TMZ+P1′ treatment is inefficient to reduce tumorgrowth. Thus, our data indicated that the use of P1 with TMZ promotedthe TMZ-induced reduction of tumor growth.

The use of P1 peptide does not promote global DNA hypomethylation andMGMT demethylation.

In glioma, MGMT methylation is associated with a good responsive ofanti-glioma treatment including TMZ and irradiation [Esteller M et al.,2000 and Hegi M et al., 2005]. Thus, we have analyzed whether the use ofP1 could modulate the methylation level of MGMT. qMSP experimentindicated that the methylation level of MGMT remains unchanged whencells were treated with P1 (data not shown)

REFERENCES

Throughout this application, various references describe the state ofthe art to which this invention pertains. The disclosures of thesereferences are hereby incorporated by reference into the presentdisclosure.

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1. An in vitro method for determining the prognosis of the survival timeof a patient suffering from a cancer comprising the steps of: i)determining the interaction level of DNMT3A/ISGF3γ in a sample from saidpatient, ii) comparing said interaction level with a predeterminedreference value, and iii) providing a good prognosis when theinteraction level is lower than the predetermined reference value and apoor prognosis when the interaction level is higher than thepredetermined reference value.
 2. An in vitro method for predicting thesurvival time of a patient suffering from a cancer and treated withconventional treatment comprising the steps of: i) determining theinteraction level of DNMT3A/ISGF3γ in a sample from said patient, ii)comparing said interaction level with a predetermined reference value,and iii) providing a good prognosis when the interaction level is lowerh the predetermined reference value and a poor prognosis when theinteraction level is higher than the predetermined reference value. 3.An in vitro method for predicting the response of a patient sufferingfrom a cancer and treated with conventional treatment comprising thesteps of: i) determining the interaction level of DNMT3A/ISGF3γ in asample from said patient, ii) comparing said interaction level with apredetermined reference value, and iii) providing a good response whenthe interaction level is lower than the predetermined reference valueand a poor response when the interaction level is higher than thepredetermined reference value.
 4. The in vitro method according to claim1, wherein the cancer is a glioblastoma.
 5. The in vitro methodaccording to claim 2, wherein the conventional treatment is temozolomideand radiation. 6-7. (canceled)
 8. A peptide comprising the amino acidssequence: RPMPRLTFQAGDPYYI (SEQ ID NO:1) or a function-conservativevariant thereof. 9-11. (canceled)
 12. A method of screening a candidatecompound for use as a drug for the prevention and treatment of cancer ina subject in need thereof, wherein the method comprises the steps of:(i) providing, DNMT3A/ISGF3γ or a cell, tissue sample or organism thatexpresses DNMT3A/ISGF3γ, (ii) contacting the DNMT3A/ISGF3γ or the cell,tissue sample or organism that expresses DNMT3A/ISGF3γ with a candidatecompound selected from the group consisting of a small organic molecule,an intra-antibody, a peptide or a polypeptide, (iii) measuring theactivity of DNMT3A/ISGF3γ or the expression of DNMT3A/ISGF3γ, and (iv)positively selecting candidate compounds that inhibit the activity orthe expression of DNMT3A/ISGF3γ.
 13. A method of treating or preventingcancer comprising administrating to a subject in need thereof atherapeutically effective amount of a compound which is a DNMT3A/ISGF3γantagonist or a compound which is a DNMT3A/ISGF3γ gene expressioninhibitor.
 14. The method of claim 13, further comprising administeringto the subject a chemotherapeutic agent and a radiotherapy or aradiotherapeutic agent.
 15. The method of claim 14, wherein the compoundwhich is a DNMT3A/ISGF3γ antagonist or a compound which is aDNMT3A/ISGF3γ gene expression inhibitor is administered simultaneously,separately or sequentially with the chemotherapeutic agent and theradiotherapy or radiotherapeutic agent.
 16. The method of claim 13,wherein the DNMT3A/ISGF3γ antagonist a peptide comprising the aminoacids sequence: RPMPRLTFQAGDPYYI (SEQ ID NO:1) or afunction-conservative variant thereof.
 17. The method of claim 16,wherein temozolomide and a radiotherapy are administered simultaneously,separately or sequentially with the peptide or function-conservativevariant thereof.
 18. The method of claim 13, wherein the cancer isglioblastoma.
 19. A method of treating cancer in a subject in needthereof, comprising i) determining an interaction level of DNMT3A/ISGF3γin a sample from said patient, ii) comparing said interaction level witha predetermined reference value, and iii) if the interaction level ishigher than the predetermined reference value, then treating the subjectby administrating a therapeutically effective amount of a compound whichis a DNMT3A/ISGF3γ antagonist or a compound which is a DNMT3A/ISGF3γgene expression inhibitor.